The introduction of electronic trading mechanisms into exchanges for securities and derivatives has been steady and relentless. The desire for immediacy of order execution and dissemination of information is one reason for the steady switch to electronic mechanisms. The simple fact that trading volume is growing, with the accompanying need for an increasingly efficient trading environment, also favors the move toward electronic trading mechanisms.
Electronic exchanges, while efficient and immediate, do not necessarily supply the liquidity available in traditional, open outcry trading environments. One reason for this is the very efficiency that electronic mechanisms bring to an exchange. The speed with which trading takes place can adversely affect market makers by exposing them to unwanted risk. For example, if movement in the underlying security needs to be reflected in the options market, rapid response times are necessary. Communication delays can prevent market makers and others from changing their quotes or orders fast enough to reflect market conditions, thereby leading to smaller quote sizes to reduce the risk. Also, electronic exchanges generally cannot match the price improvement capabilities of an open outcry exchange where floor brokers and market makers can handle large and complex orders face-to-face.